JP2021021906A - Wavelength conversion element, light source device, and display device - Google Patents

Abstract

To provide a wavelength conversion element having a high degree of freedom between wavelength selection and radiation angle control.SOLUTION: A wavelength conversion element includes: a wavelength conversion body having an incident surface and an output surface, converting primary light in a first wavelength band, which has entered the incident surface, and generating secondary light in a second wavelength band different from the first wavelength band so as to emit it from the output surface; a metal antenna group which is provided very close to the wavelength conversion body and which includes a plurality of metal antennas arranged in a manner to be separated from each other at a some distance of an optical wavelength of the secondary light in the wavelength conversion body; and a dielectric antenna group which is provided facing the output surface of the wavelength conversion body and which includes a plurality of dielectric antennas.SELECTED DRAWING: Figure 3

Description

The present invention relates to a wavelength conversion element, a light source device and a display device.

The wavelength conversion element is an optical element that converts the incident excitation light into light in a wavelength band different from the wavelength band of the excitation light, and is used as a light source of a display device such as a projector, for example. Patent Document 1 below discloses a wavelength converter including a wavelength converter including a phosphor plate and an antenna array composed of a plurality of metal antennas formed on the wavelength converter.

Japanese Unexamined Patent Publication No. 2018-13688

According to Patent Document 1, when each metal antenna is irradiated with light, the electric field intensity in the vicinity of the metal antenna is increased by the localized surface plasmon resonance on the surface of the metal antenna, the wavelength conversion light is amplified, and the angle is narrow. It is stated that the light is distributed and emitted from the antenna array.

However, in the configuration of Patent Document 1, since both the induction of plasmon resonance and the control of the radiation angle of light are realized only by the metal antenna, they are restricted from each other and the degree of freedom between wavelength selection and radiation angle control is high. There was a problem that there were few.

In order to solve the above problems, the wavelength conversion element of one aspect of the present invention has an incident surface and an emission surface, and wavelength-converts the primary light of the first wavelength band incident from the incident surface. A wavelength converter that generates secondary light in a second wavelength band different from the first wavelength band and emits the secondary light from the emission surface, and a wavelength converter that is provided in the immediate vicinity of the wavelength converter and is at a distance from each other. Is provided to face the emission surface of the wavelength converter and a group of metal antennas including a plurality of metal antennas arranged so as to be separated by a distance of about the optical wavelength of the secondary light in the wavelength converter. A group of dielectric antennas including a plurality of dielectric antennas is provided.

In the wavelength conversion element of one aspect of the present invention, the metal antenna group may have a configuration in which the plurality of metal antennas are arranged in a grid pattern on the same plane.

In the wavelength conversion element of one aspect of the present invention, the dielectric antenna group may have a configuration in which the plurality of dielectric antennas are arranged in a grid pattern on the same plane.

In the wavelength conversion element of one aspect of the present invention, the metal antenna group and the dielectric antenna group may be provided on the same layer facing the emission surface of the wavelength converter.

The wavelength conversion element of one aspect of the present invention may further include a dielectric layer covering the metal antenna group, and the dielectric antenna group faces the metal antenna group with the dielectric layer interposed therebetween. It may be provided.

The wavelength conversion element of one aspect of the present invention is further provided with a first dichroic mirror which is provided so as to face the entrance surface of the wavelength converter, transmits the primary light, and reflects the secondary light. May be good.

The wavelength conversion element of one aspect of the present invention is further provided with a second dichroic mirror which is provided so as to face the emission surface of the wavelength converter, transmits the secondary light, and reflects the primary light. May be good.

The wavelength conversion element of one aspect of the present invention may further include a light reflecting layer or a light absorbing layer provided on a surface different from the incident surface and the emitting surface of the wavelength converter.

The light source device of one aspect of the present invention includes a wavelength conversion element of one aspect of the present invention and a light source that emits the primary light to the wavelength conversion element.

The display device according to one aspect of the present invention includes a light source device according to one aspect of the present invention and an optical modulation device that modulates light from the light source device according to image information.

It is a perspective view of the wavelength conversion element of 1st Embodiment. It is a top view of the wavelength conversion element. It is sectional drawing of the wavelength conversion element along the line III-III of FIG. It is sectional drawing of the wavelength conversion element of 2nd Embodiment. It is sectional drawing of the wavelength conversion element of the 1st modification. It is sectional drawing of the wavelength conversion element of the 2nd modification. It is sectional drawing of the wavelength conversion element of 3rd Embodiment. It is a top view of the wavelength conversion element of 4th Embodiment. It is sectional drawing of the wavelength conversion element of the 3rd modification. It is sectional drawing of the wavelength conversion element of the 4th modification. It is a top view which shows another example of a metal antenna. It is a top view which shows still another example of a metal antenna. It is a top view which shows still another example of a metal antenna. It is a top view which shows still another example of a metal antenna. It is a top view which shows still another example of a metal antenna. It is a top view which shows still another example of a metal antenna. It is a top view which shows still another example of a metal antenna. It is a top view of the wavelength conversion element of 5th Embodiment. It is sectional drawing of the wavelength conversion element of 6th Embodiment. It is a schematic block diagram of a light source device. It is a schematic block diagram of a projector.

[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a perspective view of the wavelength conversion element 20 of the first embodiment. FIG. 2 is a plan view of the wavelength conversion element 20. FIG. 3 is a cross-sectional view of the wavelength conversion element 20 along the line III-III of FIG.
In each of the following drawings, in order to make each component easy to see, the scale of the dimension may be different depending on the component.

As shown in FIGS. 1 to 3, the wavelength conversion element 20 of the present embodiment includes a wavelength converter 21, a first dielectric layer 22, a metal antenna array 23 (metal antenna group), and a dielectric antenna array 24. (Dielectric antenna group) and a light reflecting layer 25 are provided. As will be described later, the light reflecting layer 25 may be a light absorbing layer.

In the present specification, the entire plurality of antennas are collectively referred to as an antenna group. Further, among the antenna groups, an antenna group in which a plurality of antennas are regularly arranged on the same plane is referred to as an antenna array.

The wavelength converter 21 has an incident surface 21a, an injection surface 21b, and four side surfaces 21c, and is formed in a rectangular shape when viewed from the normal direction of the injection surface 21b. The wavelength converter 21 performs wavelength conversion of the primary light L1 of the first wavelength band incident from the incident surface 21a to generate the secondary light L2 of the second wavelength band different from the first wavelength band, and the secondary light L2. Is injected from the injection surface 21b. The primary light L1 is, for example, light in the blue wavelength band (first wavelength band) of 440 to 450 nm. Hereinafter, the case where the injection surface 21b is viewed from the normal direction is referred to as a plan view.

The wavelength converter 21 is composed of, for example, an inorganic phosphor such as yttrium aluminum garnet (YAG: Ce) containing cerium as an activator. The wavelength converter 21 made of YAG: Ce converts a part of the primary light L1 into the secondary light L2 in the yellow wavelength band (second wavelength band) of, for example, 490 to 750 nm, and converts the secondary light L2 into the emission surface 21b. Eject from. At this time, the other part of the primary light L1 whose wavelength has not been converted into the secondary light L2 is emitted from the injection surface 21b together with the secondary light L2.

The wavelength converter 21 may be composed of an inorganic fluorescent substance such as YAG: Ce or an organic fluorescent substance obtained by dissolving an organic fluorescent dye such as lumogen or rhodamine 6G in a base material to make a thin film. In that case, for example, polymethylmethacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acrylic resin and the like can be used as the base material of the organic fluorescent dye.

The metal antenna array 23 is provided in the immediate vicinity of the wavelength converter 21. The term "extremely close to the wavelength converter 21" is defined as having a gap of 10 nm or more from the wavelength converter 21 and a gap of 1000 nm or less from the wavelength converter 21. The gap is preferably 10 nm or more and 30 nm or less. Further, as the material constituting the gap, the same material as the dielectric antenna 241 described later can be used. The refractive index of the material forming the gap is preferably within ± 0.3 with respect to the wavelength converter 21. In the case of the present embodiment, as shown in FIG. 3, the metal antenna array 23 is provided on the injection surface 21b of the wavelength converter 21 via the first dielectric layer 22. The thickness of the first dielectric layer 22 is, for example, 20 nm.

Further, it is necessary that the metal antenna array 23 is provided in the immediate vicinity of the wavelength converter 21 and is not in direct contact with the wavelength converter 21. The reason is that when the metal antenna array 23 comes into direct contact with the wavelength converter 21, the energy of the surface plasmon polariton that is resonance-induced in the vicinity of the metal antenna 231 flows to the wavelength converter 21, and the surface plasmon polariton is deactivated. Is.

The dielectric antenna array 24 is provided so as to face the injection surface 21b of the wavelength converter 21. In the case of the present embodiment, the dielectric antenna array 24 is provided on the emission surface 21b of the wavelength converter 21 via the first dielectric layer 22, similarly to the metal antenna array 23. That is, the metal antenna array 23 and the dielectric antenna array 24 are provided on the same layer facing the injection surface 21b of the wavelength converter 21.

The metal antenna array 23 has a plurality of metal antennas 231 arranged so as to be separated from each other by a distance of about the optical wavelength of the secondary light L2 in the wavelength converter 21. That is, the metal antenna array 23 has a configuration in which a plurality of metal antennas 231 are arranged in a grid pattern on the same plane. As shown in FIG. 2, the distance between the metal antennas 231 or the period P1 of the metal antenna array 23 is two metals arranged in a direction parallel to one side of the wavelength converter 21 (horizontal direction or vertical direction in FIG. 2). It is defined as the distance between the antennas 231. The optical wavelength of the secondary light L2 in the wavelength converter 21 is defined by the following equation (1).
Optical wavelength = wavelength of secondary light / refractive index of wavelength converter ... (1)

In the present specification, the optical wavelength of the secondary light L2 in the wavelength converter 21 refers to, for example, a wavelength band obtained by adding ± 50 nm to the emission wavelength band of the phosphor in the wavelength converter 21. The period P2 of the metal antenna array 23 may be defined as the distance between two metal antennas 231 arranged in an oblique direction.

On the other hand, the dielectric antenna array 24 has a plurality of dielectric antennas 241 arranged at a pitch that diffracts the secondary light L2 at a desired diffraction angle. That is, the dielectric antenna array 24 has a configuration in which a plurality of dielectric antennas 241 are arranged in a grid pattern on the same plane.

As shown in FIG. 2, in the case of the present embodiment, the plurality of metal antennas 231 and the plurality of dielectric antennas 241 are arranged in a square lattice as a whole. That is, when the topmost antenna in FIG. 2 is viewed from left to right, the metal antenna 231 is arranged at the left end, and then the dielectric antenna 241, the metal antenna 231 and the dielectric antenna 241 are made of metal. The antenna 231 and the dielectric antenna 241 are arranged alternately. Next, looking at the antenna in the second row from the top of FIG. 2 from left to right, the dielectric antenna 241 is arranged at the left end, and then the metal antenna 231, the dielectric antenna 241 and the metal antenna 231 ... Dielectric antennas 241 and metal antennas 231 are alternately arranged.

As shown in FIG. 1, each of the plurality of metal antennas 231 and each of the plurality of dielectric antennas 241 has a three-dimensional structure protruding from the wavelength converter 21 such as a columnar shape, a cone shape, and a cone shape. .. In the case of this embodiment, both the metal antenna 231 and the dielectric antenna 241 are columnar. Further, when each antenna is viewed in a plane, various shapes such as a grain shape, a circle shape, an ellipse shape, a polygonal shape, a ring shape, a linear shape, and a polygonal shape can be adopted as the plane shape of the metal antenna 231 and the dielectric antenna 241. .. Further, the shape of the metal antenna 231 and the shape of the dielectric antenna 241 may be the same or different. The arrangement of the plurality of metal antennas 231 and the plurality of dielectric antennas 241 has periodicity. The period may expand and contract at a constant rate and includes a fractal structure.

Regarding the metal antenna 231, where the maximum width of the metal antenna 231 is W1 and the height of the metal antenna 231 is h, the maximum width w1 and the height h satisfy the relationship of the following equation (2).
0.05 ≦ (h / w1) ≦ 2… (2)
However, the maximum width w1 of the metal antenna 231 is 100 nm or more.
Since the radiation angle of the dielectric antenna 241 is set so as to diffract the secondary light L2 having a desired wavelength, the dielectric antenna 241 is not restricted by the relationship of the equation (2).

As the constituent material of the metal antenna 231, for example, gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), nickel (Ni), aluminum (Al) and the like can be used. It may be an alloy of. The constituent material of the metal antenna 231 may be a material other than the above as long as it is a metal having a plasma frequency (absorption) with respect to the wavelength of the secondary light L2 to be used.

As a constituent material of the dielectric antenna 241, for example, a dielectric multilayer film used as a dielectric multilayer film such as TiO ₂ , Al ₂ O ₃ , LiNbO ₃ , HfO ₂ , Ta ₂ O ₅ , SiON, Si ₃ N _{4 and the} like in the visible region. Any material that is transparent to light can be used. Alternatively, it may be a laminate of the above materials or a mixture.

The light reflecting layer 25 is provided on a surface different from the incident surface 21a and the emitting surface 21b of the wavelength converter 21, specifically, the four side surfaces 21c of the wavelength converter 21. The light reflecting layer 25 can be composed of a metal film, a dielectric multilayer film, a microstructure, or the like formed on the side surface 21c of the wavelength converter 21. Instead of the light reflecting layer 25, light absorbing layers may be provided on the four side surfaces 21c of the wavelength converter 21. The light absorption layer can be composed of a metal film, a dielectric multilayer film, or the like formed on the side surface 21c of the wavelength converter 21.

Hereinafter, the operation of the wavelength conversion element 20 having the above configuration will be described.
As described above, when the primary light L1 is incident on the wavelength conversion element 20, the wavelength converter 21 performs wavelength conversion of the primary light L1 to generate the secondary light L2. At this time, the secondary light L2 and a part of the primary light L11 whose wavelength has not been converted into the secondary light L2 are emitted from the injection surface 21b of the wavelength converter 21.

At this time, when the secondary light L2 is incident on each metal antenna 231 of the metal antenna array 23, localized surface plasmon resonance occurs on the surface of the metal antenna 231 and the electric field strength in the vicinity of the metal antenna 231 increases. Here, since the period of the metal antenna array 23 is set to about the optical wavelength of the secondary light L2, the localized surface plasmon resonance of the adjacent metal antenna 231 causes resonance via optical diffraction, and further electric field strength. Will occur. As a result, the secondary light L2 is enhanced, and the light extraction efficiency of the secondary light is improved.

Further, since the dielectric antenna array 24 is composed of a plurality of dielectric antennas 241 arranged periodically, it functions as a diffraction grating. Therefore, when the secondary light L2 is incident on the dielectric antenna array 24, the secondary light L2 is diffracted at a predetermined diffraction angle and emitted from the dielectric antenna array 24 at a predetermined radiation angle. Assuming that the pitch of the dielectric antenna array 24 is d, the diffraction angle of the secondary light L2 is θm, the incident angle of the secondary light L2 is θ0, and the wavelength of the secondary light L2 is λ, the diffraction angle θm is as follows. It is obtained from equation (3).
d (sinθm−sinθ0) = mλ… (3)
However, m is the order of the diffracted light (a positive or negative integer).

The wavelength conversion element 20 of the present embodiment includes a metal antenna array 23 and a dielectric antenna array 24, the metal antenna array 23 is responsible for enhancing the secondary light L2, and the dielectric antenna array 24 is responsible for controlling the radiation angle. As described above, the functions are shared between the metal antenna array 23 and the dielectric antenna array 24. Further, the shape, dimensions, pitch, etc. of the dielectric antenna 241 can be set without being restricted by the shape, dimensions, pitch, etc. required by the metal antenna 231. As a result, it is possible to realize the wavelength conversion element 20 having a high degree of freedom in wavelength selection and radiation angle control.

Further, in the case of the present embodiment, since the metal antenna array 23 and the dielectric antenna array 24 are provided on the same layer, the configuration is simple and the thin wavelength conversion element 20 can be provided.

Further, in the case of the present embodiment, since the light reflecting layer 25 is provided on the side surface 21c of the wavelength converter 21, if the light reflecting layer 25 is not provided, the light is emitted from the side surface 21c of the wavelength converter 21. The light L2 can be returned to the wavelength converter 21, and the efficiency of extracting the secondary light L2 from the emission surface 21b can be improved.

Further, when the light absorption layer is provided on the side surface 21c of the wavelength converter 21, the secondary light L2 emitted from the side surface 21c of the wavelength converter 21 becomes stray light in the housing of the light source device and generates noise. The risk can be reduced.

[Second Embodiment]
Hereinafter, the second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the wavelength conversion element of the second embodiment is the same as that of the first embodiment, and the arrangement of the antenna array is different from that of the first embodiment. Therefore, the entire description of the wavelength conversion element will be omitted.
FIG. 4 is a cross-sectional view of the wavelength conversion element 30 of the second embodiment.
In FIG. 4, components common to the drawings used in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, the wavelength conversion element 30 of the present embodiment includes a wavelength converter 21, a first dielectric layer 22, a metal antenna array 33, a second dielectric layer 35, and a dielectric antenna array 34. And a light reflecting layer 25. As described above, the wavelength conversion element 30 further includes a second dielectric layer 35 that covers the metal antenna array 33. The second dielectric layer 35 of the present embodiment corresponds to the dielectric layer in the claims.

In the present embodiment, the metal antenna array 33 is provided on the injection surface 21b of the wavelength converter 21 via the first dielectric layer 22 as in the first embodiment.

Further, a second dielectric layer 35 is provided so as to cover the metal antenna array 33, and the unevenness due to the metal antenna 331 is flattened by being embedded in the second dielectric layer 35.

The dielectric antenna array 34 is provided on the upper surface of the second dielectric layer 35. In other words, the dielectric antenna array 34 is provided so as to face the metal antenna array 33 with the second dielectric layer 35 interposed therebetween. That is, in the first embodiment, the metal antenna array 23 and the dielectric antenna array 24 are provided in the same layer, whereas in the second embodiment, the metal antenna array 33 and the dielectric antenna array 34 are provided with each other. It is provided on different layers, and the dielectric antenna array 34 is provided on the upper layer side of the metal antenna array 33.

The constituent materials of the second dielectric layer 35 include the same materials as the dielectric antenna as in the first dielectric layer 22, such as TiO ₂ , Al ₂ O ₃ , LiNbO ₃ , HfO ₂ , Ta ₂ O ₅ , SiON. , Si ₃ N _{4 and the} like can be used. The thickness of the second dielectric layer 35 is, for example, 100 nm. In the present embodiment, to give an example of the film thickness of each layer, the wavelength converter 21 (YAG: Ce) is 200 μm, the first dielectric layer 22 (TiO ₂ ) is 20 nm, and the metal antenna 331 (Ag). Is 20 nm, the second dielectric layer 35 (TiO ₂ ) is 100 nm, and the dielectric antenna 341 (TiO ₂ ) is 200 nm.

In a plan view, the positional relationship between the plurality of metal antennas 331 and the plurality of dielectric antennas 341 is the same as that of the first embodiment. That is, the plurality of metal antennas 331 and the plurality of dielectric antennas 341 are arranged in a square grid as a whole, and when viewed along a direction parallel to one side of the wavelength converter 21, the metal antenna 331 and the dielectric antennas It is arranged alternately with 341.
Other configurations of the wavelength conversion element 30 are the same as those in the first embodiment.

Also in this embodiment, the same effect as in the first embodiment can be obtained, such as being able to realize the wavelength conversion element 30 having a high degree of freedom in wavelength selection and radiation angle control.

Further, in the case of the present embodiment, since the plurality of dielectric antennas 341 are provided on a layer different from the plurality of metal antennas 331 with the second dielectric layer 35 interposed therebetween, the plurality of dielectric antennas 341 can be freely arranged. The degree can be increased. For example, the following configuration of the first modification can be adopted.

(First modification)
FIG. 5 is a cross-sectional view of the wavelength conversion element 40 of the first modification.
As shown in FIG. 5, in the wavelength conversion element 40 of the first modification, among the plurality of dielectric antennas 441 constituting the dielectric antenna array 44, some of the dielectric antennas 441 are directly above the metal antenna 331. It is arranged. In other words, some dielectric antennas 441 are arranged at positions that overlap with the metal antenna 331 in a plan view. As a result, the pitch of the dielectric antenna array 44 can be freely set, such as being narrower than the pitch of the metal antenna array 33.

(Second modification)
FIG. 6 is a cross-sectional view of the wavelength conversion element 45 of the second modification.
As shown in FIG. 6, in the wavelength conversion element 45 of the second modification, the second dielectric layer 46 is composed of two dielectric layers, a base dielectric layer 461 and a flattening dielectric layer 462. There is. The base dielectric layer 461 covers each metal antenna 331 and is composed of a thin film that reflects the shape of the metal antenna 331. The flattening dielectric layer 462 further covers the underlying dielectric layer 461 and flattens the irregularities of the metal antenna 331.

In this modification, to give an example of the film thickness of each layer, for example, the wavelength converter 21 (YAG: Ce) is 200 μm, the first dielectric layer 22 (TiO ₂ ) is 20 nm, and the metal antenna 331 (Ag). ) Is 20 nm, the underlying dielectric layer 461 (TIO ₂ ) is 20 nm, the flattened dielectric layer 462 (Si ₃ N ₄ ) is 50 nm, and the dielectric antenna 341 (TIO ₂ ) is 200 nm.

The flattening dielectric layer 462 may be replaced with another type of wavelength converter. For example, by replacing the above Si ₃ N ₄ with PMMA to which Lumogen F Red (manufactured by BASF) is added, it is possible to enhance the yellow light fluorescently emitted by YAG: Ce while adding a red spectrum. Here, since the enhancement of the metal antenna 331 by the surface plasmon polariton can contribute to the wavelength converter 21 existing in the immediate vicinity, the fluorescence enhancement effect of Lumogen can also be obtained.

When the dielectric antenna array 24 is arranged in the same layer as the metal antenna array 23 as in the first embodiment, the gap between the metal antennas 231 is sewn so that the dielectric antenna 241 does not overlap with the metal antenna 231. The dielectric antenna 241 must be arranged, and the degree of freedom in the arrangement of the dielectric antenna 241 is low. On the other hand, in the case of the present embodiment, for example, as shown in FIG. 5, since the dielectric antenna 441 can be arranged at a position overlapping the metal antenna 331 in a plan view, the degree of freedom in the arrangement of the dielectric antenna 441 is high. Will be higher. As a result, according to the wavelength conversion elements 30, 40, and 45 of the present embodiment and the modified examples, it is easy to control the desired radiation angle with a higher degree of freedom.

Further, with respect to the metal antenna array 33, since it is not necessary to consider the point of radiation angle control, the degree of freedom in arranging the plurality of metal antennas 331 can be increased. Therefore, more efficient and more selective induction of surface plasmon polaritons becomes possible.

[Third Embodiment]
Hereinafter, the third embodiment of the present invention will be described with reference to FIG. 7.
The basic configuration of the wavelength conversion element of the third embodiment is the same as that of the first embodiment, and is different from the first embodiment in that two dichroic mirrors are provided. Therefore, the entire description of the wavelength conversion element will be omitted.
FIG. 7 is a cross-sectional view of the wavelength conversion element 50 of the third embodiment.
In FIG. 7, components common to the drawings used in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 7, the wavelength conversion element 50 of the present embodiment includes a wavelength converter 21, a first dielectric layer 22, a metal antenna array 33, a second dielectric layer 35, and a dielectric antenna array 44. A light reflecting layer 25, a first dichroic mirror 51, and a second dichroic mirror 52 are provided.

The first dichroic mirror 51 is provided so as to face the incident surface 21a of the wavelength converter 21. The first dichroic mirror 51 is composed of a dielectric multilayer film. The first dichroic mirror 51 has a spectral characteristic of transmitting light in the blue wavelength band and reflecting light in the yellow wavelength band. Therefore, the first dichroic mirror 51 transmits the primary light L1 traveling toward the incident surface 21a of the wavelength converter 21 from the outside, and reflects the secondary light L2 generated inside the wavelength converter 21.

In the present embodiment, as in the second embodiment shown in FIG. 4, a second dielectric layer 35 is provided so as to face the injection surface 21b of the wavelength converter 21 and cover the metal antenna array 33. The second dichroic mirror 52 is provided on the second dielectric layer 35 so as to face the injection surface 21b of the wavelength converter 21. The dielectric antenna array 44 is provided on the second dichroic mirror 52. The second dichroic mirror 52 is composed of a dielectric multilayer film. The second dichroic mirror 52 has a spectral characteristic of transmitting light in the yellow wavelength band and reflecting light in the blue wavelength band. Therefore, the second dichroic mirror 52 transmits the secondary light L2 emitted from the emission surface 21b of the wavelength converter 21 and reflects the primary light L1 that has passed through the inside of the wavelength converter 21.
Other configurations of the wavelength conversion element 50 are the same as those in the first embodiment.

Also in this embodiment, the same effect as in the first embodiment can be obtained, such as being able to realize the wavelength conversion element 50 having a high degree of freedom in wavelength selection and radiation angle control.

Further, in the case of the present embodiment, since the first dichroic mirror 51 that reflects the secondary light L2 is provided so as to face the incident surface 21a of the wavelength converter 21, it is generated inside the wavelength converter 21. It is possible to suppress the leakage of the secondary light L2 from the incident surface 21a to the outside, and reduce the loss of the secondary light L2.

Further, since the second dichroic mirror 52 that reflects the primary light L1 is provided so as to face the emission surface 21b of the wavelength converter 21, the primary light L1 that reaches the emission surface 21b without wavelength conversion is converted into a wavelength converter. It can be returned to to contribute to wavelength conversion, and the conversion efficiency of the primary light L1 can be improved.

In the case of the present embodiment, since the second dichroic mirror 52 is provided, a part of the primary light L11 is not emitted from the wavelength conversion element 50, so that the light emitted from the wavelength conversion element 50 is a yellow secondary light. Only light L2. Therefore, when the wavelength conversion element 50 is used for the purpose of obtaining white light, an antireflection film may be provided instead of the second dichroic mirror 52.

[Fourth Embodiment]
Hereinafter, the fourth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the wavelength conversion element of the fourth embodiment is the same as that of the first embodiment, and the configuration of the metal antenna array is different from that of the first embodiment. Therefore, the entire description of the wavelength conversion element will be omitted.
FIG. 8 is a plan view of the wavelength conversion element 60 of the fourth embodiment. Note that FIG. 8 shows only the metal antenna array 61, and the dielectric antenna array is not shown. The dielectric antenna array may be provided on the same layer as the metal antenna array 61, or may be provided on a layer different from the metal antenna array 61.
In FIG. 8, components common to the drawings used in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, in the wavelength conversion element 60 of the present embodiment, the metal antenna array 61 has a plurality of metal antennas 611. In the plurality of metal antennas 611, the metal antennas 611 in rows adjacent to each other in the vertical direction are arranged so as to be offset by half a pitch in the horizontal direction. In this way, the plurality of metal antennas 611 are arranged in a so-called oblique lattice pattern. The planar shape of each metal antenna 611 is elliptical.
Other configurations of the wavelength conversion element 60 are the same as those in the above embodiment.

Also in this embodiment, the same effect as that of the first embodiment can be obtained, such that the wavelength conversion element 60 having a high degree of freedom in wavelength selection and radiation angle control can be realized.

The arrangement of the plurality of metal antennas 611 may be the following modification.
(Third modification example)
FIG. 9 is a plan view of the wavelength conversion element 63 of the third modification.
As shown in FIG. 9, in the wavelength conversion element 63 of this modification, the metal antenna array 64 has a plurality of metal antennas 641. The plurality of metal antennas 641 are arranged in a rectangular grid pattern at different pitches in the vertical direction and the horizontal direction. The planar shape of each metal antenna 641 is rectangular.

(Fourth modification)
FIG. 10 is a plan view of the wavelength conversion element 66 of the fourth modification.
As shown in FIG. 10, in the wavelength conversion element 66 of this modification, the metal antenna array 67 has a plurality of metal antennas 671. In the plurality of metal antennas 671, the metal antennas 671 in rows adjacent to each other in the vertical direction are arranged so as to be offset by half a pitch in the horizontal direction. In this way, the plurality of metal antennas 671 are arranged in a so-called hexagonal lattice. The shape of each metal antenna 671 is a conical trapezoid.

Further, the shape of each metal antenna 611 may be a modified example as follows.
11 to 17 are plan views showing other shape examples of the metal antenna.
As shown in FIG. 11, the shape of the metal antenna 681 may be L-shaped.
As shown in FIG. 12, the shape of the metal antenna 682 may be a hexagonal shape.
As shown in FIG. 13, the shape of the metal antenna 683 may be trapezoidal.
As shown in FIG. 14, the shape of the metal antenna 684 may be cross-shaped.
As shown in FIG. 15, the shape of the metal antenna 685 may be a shape in which a part of a circle is cut out in a fan shape.
As shown in FIG. 16, the shape of the metal antenna 686 may be a rectangular ring shape.
As shown in FIG. 17, the shape of the metal antenna 687 may be a shape in which a part of the ring is interrupted.

As shown above, the arrangement and shape of the metal antenna can be selected with a high degree of freedom. Further, among the above arrangements and shapes, metal antennas having different arrangements and shapes may be combined. For example, by combining metal antennas having different shapes, it is possible to control the electric field intensity or electric field distribution of the surface plasmon polaritons induced in the plane of the wavelength conversion element.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the wavelength conversion element of the fifth embodiment is the same as that of the first embodiment, and the configuration of the metal antenna array is different from that of the first embodiment. Therefore, the entire description of the wavelength conversion element will be omitted.
FIG. 18 is a plan view of the wavelength conversion element 70 of the fifth embodiment. In FIG. 18, only the metal antenna array 71 is shown, and the dielectric antenna array is not shown. The dielectric antenna array may be provided on the same layer as the metal antenna array 71, or may be provided on a layer different from the metal antenna array 71.
In FIG. 18, components common to the drawings used in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 18, in the wavelength conversion element 70 of the present embodiment, the metal antenna array 71 has a plurality of metal antennas 711. The plurality of metal antennas 711 are arranged concentrically with a predetermined pitch along the circumferential direction. The pitch along the circumferential direction of the metal antennas 711 lined up on each circle is different for each circle. In the case of the present embodiment, the pitch of the metal antennas 711 arranged on the circle near the center of the wavelength conversion element 70 is narrow, and the pitch of the metal antennas 711 arranged on the circle near the peripheral edge of the wavelength conversion element 70 is wide. ..
Other configurations of the wavelength conversion element 70 are the same as those in the above embodiment.

Also in this embodiment, the same effect as in the first embodiment can be obtained, such as being able to realize the wavelength conversion element 70 having a high degree of freedom in wavelength selection and radiation angle control.

As in the present embodiment, the pitch of the metal antenna 711 does not necessarily have to be constant in the plane of the wavelength conversion element 70, and may expand or contract depending on the location regardless of various arrangements such as concentric circles and square grids. You may. By changing the arrangement and pitch of the metal antenna 711 in the plane in this way, it is possible to control the electric field intensity or the electric field distribution of the surface plasmon polariton induced in the plane of the wavelength conversion element 70.

[Sixth Embodiment]
Hereinafter, the sixth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the wavelength conversion element of the sixth embodiment is the same as that of the first embodiment, and the configuration of the metal antenna array is different from that of the first embodiment. Therefore, the entire description of the wavelength conversion element will be omitted.
FIG. 19 is a cross-sectional view of the wavelength conversion element 80 of the sixth embodiment.
In FIG. 19, components common to the drawings used in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 19, the wavelength conversion element 80 of the present embodiment includes a wavelength conversion body 21, a metal antenna group 81, a dielectric antenna array 44, and a light reflection layer 25. In the case of the present embodiment as well, the light reflecting layer 25 may be a light absorbing layer as in the first embodiment.

The metal antenna group 81 has a plurality of metal antennas 811 dispersed inside the wavelength converter 21. Each of the plurality of metal antennas 811 is composed of metal particles 812 and a dielectric coating layer 813 that surrounds the metal particles 812. The thickness of the dielectric coating layer 813 is preferably 10 nm or more and 30 nm or less, as in the case of the first dielectric layer 22 of the first embodiment. In the case of the present embodiment, due to such a structure, the metal antenna group 81 does not come into direct contact with the wavelength converter 21 and is located in the very vicinity of the wavelength converter 21. In the wavelength converter 21 of the present embodiment, for example, when Lumgen F Red as a phosphor particle is dispersed in PMMA, metal particles having a diameter of about 100 nm coated with a dielectric material are simultaneously dispersed. It can be manufactured.

In the case of the present embodiment, since the metal antenna group 81 is arranged inside the wavelength converter 21, the first dielectric layer 22 is not provided on the injection surface 21b of the wavelength converter 21, and the dielectric is a dielectric. Only the antenna array 44 is provided.
Other configurations of the wavelength conversion element 80 are the same as those of the first embodiment.

Also in this embodiment, the same effect as in the first embodiment can be obtained, such as being able to realize the wavelength conversion element 80 having a high degree of freedom in wavelength selection and radiation angle control.

In particular, in the case of the present embodiment, since localized plasmon is induced in the vicinity of the metal particles 812, enhancement of the secondary light L2 (fluorescence) having a wavelength corresponding to the type and particle size of the metal can be expected. When the localized plasmon is used, unlike the surface plasmon polariton, the electric field strengthening intensity on the surface becomes small, but the enhancement can be promoted as a whole volume of the wavelength converter 21.

Further, also in the case of the present embodiment, as in the second embodiment and the like, since the plurality of dielectric antennas 441 are not arranged on the same layer as the plurality of metal antennas 811, the degree of freedom in the arrangement of the plurality of dielectric antennas 441 is increased. Can be enhanced. This has the effect that the desired radiation angle can be easily controlled with a higher degree of freedom. In particular, in the case of the present embodiment, the plurality of metal antennas 811 are not on the same plane and are randomly dispersed inside the wavelength converter 21. Therefore, a desired pitch range between the metal antennas 811 can be realized by appropriately adjusting the concentration of the metal particles in the manufacturing process.

(Light source device)
Hereinafter, the light source device according to the embodiment of the present invention will be described.
FIG. 20 is a schematic configuration diagram of the light source device 2.

As shown in FIG. 20, the light source device 2 includes a light source unit 11 and a uniform illumination optical system 12.

The light source unit 11 includes a light source 13, a collimator optical system 14, a first condensing optical system 15, a rod integrator 16, a second condensing optical system 17, a wavelength conversion element 20, and a pickup optical system 18. , Is equipped. The light source 13 emits the primary light L1 toward the wavelength conversion element 20.

The light source 13 is composed of a plurality of semiconductor lasers 131 that emit blue primary light L1 having a first wavelength band. The primary light L1 is light in the blue wavelength band (first wavelength band) of 440 to 450 nm, which has a peak wavelength of emission intensity of 445 nm. The plurality of semiconductor lasers 131 are arranged in an array in one plane orthogonal to the illumination optical axis AX1. The semiconductor laser 131 may emit primary light L1 having a peak wavelength other than 445 nm, for example, a peak wavelength of 455 nm or 460 nm.

The collimator optical system 14 is provided between the light source 13 and the first condensing optical system 15. The collimator optical system 14 is composed of a plurality of collimator lenses 141. The collimator lens 141 is provided corresponding to each semiconductor laser 131, and is arranged in an array in one plane orthogonal to the illumination optical axis AX1. The collimator lens 141 parallelizes the primary light L1 emitted from the corresponding semiconductor laser 131.

The first condensing optical system 15 is provided between the collimator optical system 14 and the rod integrator 16. The first condensing optical system 15 condenses the primary light L1 emitted from the collimator optical system 14 and causes it to enter the rod integrator 16. The first condensing optical system 15 is composed of, for example, a convex lens. The first condensing optical system 15 may be composed of a plurality of lenses.

The rod integrator 16 is provided between the first condensing optical system 15 and the second condensing optical system 17. The rod integrator 16 is composed of a square columnar light transmitting member, and has a light incident end surface 16a, a light emitting end surface 16b, and four reflecting surfaces 16c. The intensity distribution of the primary light L1 is made uniform by passing through the rod integrator 16 while repeating reflection on the reflecting surface 16c of the rod integrator 16.

The second condensing optical system 17 is provided between the rod integrator 16 and the wavelength conversion element 20. The second condensing optical system 17 condenses the primary light L1 emitted from the rod integrator 16 and causes it to enter the wavelength conversion element 20. The second condensing optical system 17 is composed of, for example, a first lens 171 made of a convex lens and a second lens 172.

The wavelength conversion element 20 wavelength-converts the primary light L1 emitted from the light source 13 to generate the secondary light L2, and from the secondary light L2 and a part of the light L11 of the primary light L1 that has not been wavelength-converted. White light LW is emitted. As the wavelength conversion element 20, any wavelength conversion element of the above embodiment may be used.

The pickup optical system 18 is provided between the wavelength conversion element 20 and the uniform illumination optical system 12. The pickup optical system 18 parallelizes the white light LW emitted from the wavelength conversion element 20 and guides it to the uniform illumination optical system 12. The pickup optical system 18 is composed of, for example, a convex lens. The pickup optical system 18 may be composed of a plurality of lenses.

The uniform illumination optical system 12 includes a first lens array 91, a second lens array 92, a polarization conversion element 93, and a superimposing lens 94.

The first lens array 91 has a plurality of first lenses 911 for dividing the white light LW emitted from the pickup optical system 18 into a plurality of partial luminous fluxes. The plurality of first lenses 911 are arranged in a matrix in a plane orthogonal to the illumination optical axis AX1.

The second lens array 92 has a plurality of second lenses 921 corresponding to the plurality of first lenses 911 of the first lens array 91. The second lens array 92, together with the superimposing lens 94, forms an image of each first lens 911 of the first lens array 91 in the vicinity of the image forming region of the optical modulation devices 4R, 4G, and 4B. The plurality of second lenses 921 are arranged in a matrix in a plane orthogonal to the illumination optical axis AX1.

The polarization conversion element 93 has a function of aligning the polarization directions of the white light LW in one direction. Although not shown, the polarization conversion element 93 includes a polarization separation membrane, a retardation plate, and a mirror. The polarization conversion element 93 converts the other polarization component into one polarization component in order to align the polarization directions of the white light LW. The polarization conversion element 93 converts, for example, a P polarization component into an S polarization component.

The superimposing lens 94 collects each partial luminous flux from the polarization conversion element 93 and superimposes them on each other in the vicinity of the image forming region of the optical modulation devices 4R, 4G, and 4B. The first lens array 91, the second lens array 92, and the superimposed lens 94 constitute an integrator optical system that makes the in-plane light intensity distribution of the white light LW uniform.

The light source device 2 of the present embodiment includes the wavelength conversion element 20 of the above embodiment, and the white light enhanced by the wavelength conversion element 20 is emitted from the wavelength conversion element 20 at a desired radiation angle. There is little light eclipse in the optical system in the latter stage of 20. Therefore, it is possible to realize the light source device 2 having high light intensity and high light utilization efficiency.

(projector)
Hereinafter, the projector 1 (display device) according to the embodiment of the present invention will be described.
FIG. 21 is a schematic configuration diagram of the projector 1.

As shown in FIG. 21, the projector 1 of the present embodiment is a projection type image display device that displays a color image on the screen SCR. The projector 1 includes a light source device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a composite optical system 5, and a projection optical device 6. As the light source device, the light source device of the above embodiment shown in FIG. 20 is used.

The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a reflection mirror 8a, a reflection mirror 8b, a reflection mirror 8c, a relay lens 9a, and a relay lens 9b. .. The color separation optical system 3 separates the white light LW emitted from the light source device 2 into red light LR, green light LG, and blue light LB, guides the red light LR to the light modulator 4R, and emits the green light LG. It leads to the modulator 4G and leads the blue light LB to the optical modulator 4B.

The field lens 10R is arranged between the color separation optical system 3 and the light modulation device 4R, substantially parallelizes the incident light, and emits the incident light toward the light modulation device 4R. The field lens 10G is arranged between the color separation optical system 3 and the light modulation device 4G, substantially parallelizes the incident light, and emits the incident light toward the light modulation device 4G. The field lens 10B is arranged between the color separation optical system 3 and the light modulation device 4B, substantially parallelizes the incident light, and emits the incident light toward the light modulation device 4B.

The first dichroic mirror 7a transmits a red light component and reflects a green light component and a blue light component. The second dichroic mirror 7b reflects the green light component of the light reflected by the first dichroic mirror 7a and transmits the blue light component. The reflection mirror 8a reflects the red light component transmitted through the first dichroic mirror 7a. The reflection mirror 8b and the reflection mirror 8c reflect the blue light component transmitted through the second dichroic mirror 7b.

The red light LR transmitted through the first dichroic mirror 7a is reflected by the reflection mirror 8a, passes through the field lens 10R, and is incident on the image forming region of the light modulator 4R for red light. The green light LG reflected by the first dichroic mirror 7a is further reflected by the second dichroic mirror 7b, passes through the field lens 10G, and is incident on the image forming region of the light modulator 4G for green light. The blue light LB transmitted through the second dichroic mirror 7b passes through the relay lens 9a, the reflection mirror 8b on the incident side, the relay lens 9b, the reflection mirror 8c on the emission side, and the field lens 10B, and then the light modulator 4B for blue light. It is incident on the image forming region.

Each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B modulates the incident colored light according to the image information to form the image light. Each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B is composed of a liquid crystal light bulb. Although not shown, the polarizing plates on the incident side are arranged on the light incident side of the optical modulation device 4R, the optical modulation device 4G, and the light modulation device 4B, respectively. Ejection side polarizing plates are arranged on the light emission side of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

The synthetic optical system 5 synthesizes each image light emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B to form a full-color image light. The synthetic optical system 5 is composed of a cross-dichroic prism in which four right-angled prisms are bonded together to form a substantially square shape in a plan view. A dielectric multilayer film is formed at a substantially X-shaped interface in which right-angled prisms are bonded to each other.

The image light emitted from the synthetic optical system 5 is magnified and projected by the projection optical device 6, and forms an image on the screen SCR. That is, the projection optical device 6 projects the light modulated by the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. The projection optical device 6 is composed of a plurality of projection lenses.

Since the projector 1 of the present embodiment includes the light source device 2 of the above embodiment, the light utilization efficiency is excellent and a bright image can be obtained.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, a plurality of dielectric antennas constituting the dielectric antenna array are arranged in a two-dimensional manner, but instead of this configuration, a linear dielectric antenna extending in a predetermined direction is provided. However, it may be a wavelength conversion element having a configuration in which a plurality of dielectric antennas are arranged one-dimensionally in a direction orthogonal to the extending direction of each dielectric antenna. That is, as the dielectric antenna group, a dielectric antenna group including a plurality of linear dielectric antennas and a plurality of slit portions located between adjacent dielectric antennas may be used.

In addition, the specific description of the shape, number, arrangement, material, and the like of each component of the wavelength conversion element, the light source device, and the projector is not limited to the above embodiment, and can be appropriately changed. In the above embodiment, an example in which the light source device according to the present invention is mounted on a projector using a liquid crystal light bulb is shown, but the present invention is not limited to this. The light source device according to the present invention may be mounted on a projector using a digital micromirror device as a light modulation device.

Further, in the above embodiment, an example in which the light source device according to the present invention is mounted on the projector is shown, but the present invention is not limited to this. The light source device according to the present invention can also be applied to lighting equipment, automobile headlights, and the like.

1 ... Projector, 2 ... Light source device, 4R, 4G, 4B ... Light modulator, 13 ... Light source, 20, 30, 40, 45, 50, 60, 63, 66, 70, 80 ... Wavelength conversion element, 21 ... Wavelength Transformant, 21a ... Incident surface, 21b ... Ejection surface, 23,33,61,64,67,71 ... Metal antenna array (metal antenna group), 24,34,44 ... Dielectric antenna array (dielectric antenna group) , 25 ... light reflection layer, 35, 46 ... second dielectric layer (dielectric layer), 51 ... first dichroic mirror, 52 ... second dichroic mirror, 81 ... metal antenna group, 231, 331, 611, 641, 671,681,682,683,684,685,686,687,711,811 ... Metal antenna, 241,341,441 ... Dielectric antenna, L1 ... Primary light, L2 ... Secondary light.

Claims (10)

It has an incident surface and an ejection surface, and wavelength-converts the primary light of the first wavelength band incident from the incident surface to generate secondary light of a second wavelength band different from the first wavelength band. A wavelength converter that emits secondary light from the injection surface,
A group of metal antennas including a plurality of metal antennas provided in the immediate vicinity of the wavelength converter and arranged so as to be separated from each other by a distance of about the optical wavelength of the secondary light in the wavelength converter.
A dielectric antenna group provided so as to face the injection surface of the wavelength converter and including a plurality of dielectric antennas,
Wavelength conversion element equipped with. The wavelength conversion element according to claim 1, wherein the metal antenna group has a configuration in which the plurality of metal antennas are arranged in a grid pattern on the same plane. The wavelength conversion element according to claim 1 or 2, wherein the dielectric antenna group has a configuration in which the plurality of dielectric antennas are arranged in a grid pattern on the same plane. The invention according to any one of claims 1 to 3, wherein the metal antenna group and the dielectric antenna group are provided on the same layer facing the emission surface of the wavelength converter. Wavelength conversion element. Further provided with a dielectric layer covering the metal antenna group,
The wavelength conversion element according to any one of claims 1 to 3, wherein the dielectric antenna group is provided so as to face the metal antenna group with the dielectric layer interposed therebetween. Any one of claims 1 to 5, further comprising a first dichroic mirror provided so as to face the incident surface of the wavelength converter, transmit the primary light, and reflect the secondary light. The wavelength conversion element according to the item. Any one of claims 1 to 6, further comprising a second dichroic mirror provided so as to face the emission surface of the wavelength converter, transmit the secondary light, and reflect the primary light. The wavelength conversion element according to the item. The wavelength conversion according to any one of claims 1 to 7, further comprising a light reflecting layer or a light absorbing layer provided on a surface different from the incident surface and the emitting surface of the wavelength converter. element. The wavelength conversion element according to any one of claims 1 to 8.
A light source that emits the primary light to the wavelength conversion element,
A light source device equipped with. The light source device according to claim 9 and
An optical modulation device that modulates the light from the light source device according to image information,
A display device equipped with.

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